Chemical product and process for making the same



Patented Feb. 12, 1946 UNITED STATE CHEMICAL PRODUCT AND PROCESS/FORMAKING THE SAME Thomas A. Ford, Wilmington, Del, ammo;- to

E. I. du Pont de Nemours & Company, Wil mington, Del, a corporation ofDelaware No Drawing. Application April 2:, 1943, Serial No. 484,212

9 Claims. (Cl. 260-505) This invention relates to new polysulfonic acidsand a process for their preparation.

It is known that certain polybasic acids are of value as assistants inthe tanning of leather and as dispersing agents or detergents. Thepolysulfonic acids prepared by the sulfonation of polystyrene are knownto show such properties to some extent. However, the usefulness ofsynthetic products in tanning leather or aiding dispersion, etc.,depends upon a complex combination of physical and chemical properties,and the sulfonated polystyrenes are not entirely satisfactory for thesepurposes. Furthermore, polystyrene is not easily sulfonated, and thequality of the products may vary considerably from batch to batchwithout apparent cause.

It is an object of this invention to prepare new polysulfonic acids.Another object is to provide new polysulfonic acids having at least oneother substituent. A further object is to prepare sulfonated aromatictelomers. Other objects will appear hereinafter.

These objects have been accomplished by sulfonating the aromatic nucleiof a telomer, each taxomon unit of which contains an aromatic nucleus,thereby producing a polysulfonic acid.

Telomers are new types of compounds produced by a process calledtelomerization. In copending U. S. application Serial No. 438,466, filedApril 10, 1942, it has been pointed out that the novelty of thisreaction is such that, for adequate description, it has been foundnecessary to coin new terms to describe the reaction and theparticipants therein. The reaction has been called telomerization (fromGreek telos, meaning end plus Greek mer meaning part) Telomerization isdefined as the process of reacting, under polymerization conditions, amolecule YZ which is called a telogen" with more than one unit of apolymerizable compound having ethylenic unsaturation called a taxogen toform products called telomers having the formula Y(A)1LZ, wherein (AM isa divalent radical formed by the chemical union, with the formation ofnew carbon bonds, of the taxogen, the unit A being called a taxomon, nbeing any integer greater than one, and Y and Z being fragments of thetelogen attached to the terminal taxomons. Telomers of aromatic taxogensare new compositions of matter described in pending U. S. applicationSerial No. 464,519, filed November 4, 1942. They are prepared by thereaction of aromatic taxogens, i. e., polymerizable olefinic compoundscontaining aromatic substituents (such tillation or steam as styrene,vinyl benzoate, etc.) with telogens, i. e., telomerizing agents (such ascarbon tetrachloride, ethyl trichloroacetate, hydrochloric acid, etc.).The preparation of such telomers is fully described in U. S. applicationSerial No. 464,519, filed November 4, 1942, which is made a. part ofthis disclosure by reference. 7

A monomeric taxogen, such as styrene, is heated with 1 to 3 molecularequivalents of a telogen v and approximately 0.01 molecular equivalentof a telomerization catalystsuch as benzoyl peroxide, at to 200 C. for aperiod of about 8 hours. The product is separated from the excess oftelogen and from any remaining monomeric styrene by a suitable process,such as, for example, disdistillation. The reaction temerature and theconcentrations of the reactants are chosen to give a product having thedesired molecular weight, according to the general rule that the averagemolecular weight of the product is decreased by using a highertemperature or by increasing the concentration or the telogen.

When one mole of styrene is heated with two moles of carbontetrachloride and 0.004 mole of benzoyl peroxide at 86 C. for '10 hours,the product, C1(CzH3.CeH5)nCC1'- is found to have an average chainlength, n, of 21 styrene units. When 1.3 moles of carbon tetrachlorideare used and the temperature is maintained at C. for 8 hours, theproduct is found to have a chain length, n, of 15. When styrene isheated with 2 moles of bromoform and 0.0066 mole of benzoyl peroxide at90 to 120 C. for 24 hours, the product, after separation from excessbromoform by distillation under diminished pressure, is found to have anaverage chain length of 8 styrene units. Ethyl trichloroacetate gives aproduct of even lower molecular weight.

A telomer of an aromatic taxogen is treated with a sulfonating agent toproduce a polysulfonic acid. The product contains a multiplicity ofsulfonic acid groups and at least one other substituent, the latterbeing derived from a fragment of the telogen used in the preparation ofthe telomer. By sulfonating agent is meant any reagent capable ofintroducing a sulfonic acid group into a benzenoid nucleus. It has beenfound that the telomers may be sulfonated by the same reagents known tobe effective for monomeric aromatic organic compounds, for exampleconcentrated sulfuric acid or chlorosulfonic acid.

In order that the invention may be more fully understood, the followingexamples are given by 7 way of illustration. Parts are by weight.

,E'wample I One part of a styrene/carbon tetrachloride telomer having anaverage composition of Cl-(CzI-IaCcHs) i-CC1: (calculated on the basisof the chlorine content of 8.39%) is finely powdered and mixed with 9parts of concentrated sulfuric acid. The mixture is mechanically stirredduring heating at 100 to 110 C. for three hours. Hydrogen chloride isevolved and the mixture darkens somewhat. After cooling toroomtemperature, the mixture is poured on ice. The resulting solution isof value as a tanning assistant and as a wetting agent. To isolate thefree acid in pure condition, the solution is placed in a Cellophane bagand dialy'zed in'running water until free of sulfate ion, as indicatedby testing the wash water. If the solution is diluted ,suificiently, theCellophane is not attacked by the acid during the dialysis. However, itis sometimes advantageous to partially neutralize the solution withsodium hydroxide before carrying out the dialysis. The free acid isobtained in pure, dry'condition by evaporating the dialyzed solution. Itis a brittle solid, soluble in water but insoluble in,all common organicsolvents. It contains no chlorine, showing that hydrolysis hassimultaneously occurred, the CO1: group being in all probabilityhydrolyzed to a COOK group. The sulfur content, 15.85%, shows that onthe average the molecule contains approximately one sulfonic acid groupper styrene unit.

Example III I Two hundred twenty-five parts of a styrene/carbontetrachloride telomer having an average composition ofC'l(C2Ha.CoHs)1o-CC1:

is dissolved in 900 parts of ethylene dichloride.

By fractional crystallization of the styrene telomer itself individualcompounds may be obtained. These can be sulfonated as above to give thecorresponding sulfonated compound having'the formula wherein n is aninteger from 2 to 30, a: is an integer having a value from 2 to 2n, M isa member of the group consisting of hydrogen and positive salt-formingradicals and the SO:M radicals are substituted for hydrogen in thearomatic nuclei.

Example IV One part of a styrene/CHCI: telomer having an averagecomposition l-lwzHaCeflahaCCla is finely ground and mixed with 10 parts01-" 0011- heated at 100 and stirred for 16 hours. It is then It thencontains 19.8% of active ingredient.

poured into ice water. The resulting product is soluble in water.

Example V One part of a finely ground telomer having the averagecomposition of C1(C2H3C6H5)i8CC13, after reaction with 4 parts of 96%sulfuric acid at 100 C. for 5 hours, is drowned in ice and filtered. Thewater-soluble sulfonic acid solution is then neutralized by the additionof 2.9 parts of sodium hydroxide. The resulting. solution of sodiumsalts is useful in tanning applications.

A polysulfonic acid can be prepared from any telomer containing aromaticnuclei. Preferably the telomer has from 5 to 30 taxomon units, each ofwhich contains an aromatic hydrocarbon nucleus. It is also preferredthat the telomer have a halogen in an end group.

The taxogens can be aromatic compounds, having side chain olefinicunsaturation, such as styrene, alpha-methyl styrene, beta-ethyl styrene,l-vinyl 4 chloro-benzene, 1,4-divinyi-benzene, vinyl naphthalenes,indene, etc. The preferred taxogens are polymerizable aromaticmono-olefinic hydrocarbons. Especially preferred are aromatic vinylcompounds of from 8 to 12 carbon atoms, such as styrene, nuclearsubstituted styrenes, and vinyl naphthalene.

Hydrogen chloride is a suitable telogen. Halogenated derivatives ofaliphatic hydrocarbons, such as C014, CHCla, CHzClz, CHaClI, CHsCCla,CHzBr, and especially halogenated methanes having at least two halogenatoms, are preferred.

The lower molecular weight,'gummy telomers are readily soluble in thesulfonation mixtures, while the higher molecular weight telomers arebrittle and may easily be reduced to a fine powder and dispersed in thesulfonation mixture. As illustrated in the examples, the telomer may beeither warmed with concentrated sulfuric acid or dissolved in an inertsolvent such as ethylene dichloride and treated with chlorosulfonicacid. The product is obtained by drowning the mixture in water. Itis-then ready for use, but if desired it may be neutralized with causticand further purified by suitable means, e. g., dialysis. The conditionsused for the sulfonation vary with the sulfonating agent employedand'thetype of prod uctdesired. In the examples, conditions suitable forthe introduction of approximately one sulfonic acid group per styreneresidue have been indicated, but it is possible to employ much lowertemperatures for the introduction of only a few sulfonic acid groups permolecule or much higher temperatures for the introduction of more thanone sulfonic acid group per styrene unit without causing excessivedegradation of the molecule.

The free acids can be converted into their salts, preferably theirwater-soluble salts, such as alkali metal salts, especially sodium andpotassium, ammonium salts, amine salts, etc. The salts are frequentlymore desirable than the free acid where it is desired to isolate and drythe product for storage or shipment. The water-soluble salts haveproperties similar to the free acids.

The process of the invention produces new compounds, usually as mixturesof compounds differing in the length of the telomer chain and the numberof sulfonic acid groups. These compounds can be represented by theformula wherein n is an integer having an average value of from 2 to 30,a: is an integer having an average value of from 2 to 212, (AM; is adivalent radical formed by condensation of a polymerizable aromaticmono-olefinic compound, the end radicals Y and Z are fragments of amolecule YZ which has been made to react with the olefin, M is a memberof the group consisting of H and positive salt-forming radicals, and theSOaM groups are substituted for hydrogen (represented by the minus H1:in the formula), in aromatic nuclei. Preferably as equals 11; i. e.,there is one sulfonic acid radical per aromatic nucleus.

The products are useful as intermediates for the production ofdispersing agents, surfaceactive agents, dyestuffs, and pigments.

Aqueous solutions of sulfonated telomers, e. g., those prepared fromstyrene and C014, which have been freed of impurities, exert apronounced bleaching or lightening of color when applied to chrometanned leather and thus are advantageous for the preparation of whitechrome leather. This effect is obtained by adding from 5 to percent ofthe active telomer at pH values from 1.5 to 3.0, to freshly tanned andshaved chrome leather in accordance with the general practice forsyntans.

The mixtures of telomers may be separated into individual telomers bymolecular distillation,

fractional crystallization, fractional precipitation, etc. Fractionalcrystallization is' preferred in the separation of the individualsulfonated telomers. The individual sulfonated telomers have the formulahaving the values above given. 7

It is apparent that many widely different embodiments of this inventionmay be made without departing from the spirit and scope thereof, and,therefore, it is not intended to be limited except as indicated in theappended claims.

I claim:

1. A mixture of linear polymeric materials having substituted bysulfonic acid groups hydrogen on nuclear carbon of linear polymericmaterials having a chain of two to thirty units, a chlorine atomsatisfying one terminal valence of said chain and a -CC13 groupsatisfying the other terminal valence of said chain.

2. A mixture of linear polymeric materials having substituted bysulfonic acid groups hydrogen on nuclear carbon of linear polymericmaterials having a, chain of two to thirty units and, terminally, twomonovalent radicals which together form a polychlorinated methane.

3. A mixture of linear polymeric materials having substituted bysulfonic acid groups hydrogen on nuclear carbon of linear polymericmaterials having a chain of two to thirty CH-C1ir units and, terminally,two monovalent radicals which together form a polyhalogenated methane.

4. A mixture of linear polymeric materials have ing substituted bysulfonic acid groups hydrogen on nuclear carbon of linear polymericmaterials having a chain of two to thirty having a chain of two tothirty -on-om- R groups, R being a monovalent aromatic hydro carbonradical, and, terminally, two monovalent radicals which together form apolychlorlnated methane.

6. A mixture of linear polymeric materials hav- F ing substituted bysulfonic acid groups hydrogen a on nuclear carbon of linear polymericmaterials having a chain of two to thirty CHCH2;

groups, R being a monovalent aromatic hydrocarbon radical, and,terminally, two monovalent radicals which together form apolyhalogenated groups. B being a monovalent aromatic radical,

and, terminally, .two monovalent radicals which together form apolyhalogenated methane.

8. A mixture of linear polymeric materials having substituted, bysubstituents of the class consisting of the sulfonic acid group andmetal salts thereof, hydrogen on nuclear carbon of linear polymericmaterials having a chain of two to thirty --CH--CHI Cu I units and,terminally, two monovalent radicals which together form apolyhalogenated methane.

9. A mixture of linear polymeric materials having substituted, bysubstituents of the class consisting of the sulfonic acid group andmetal salts thereof, hydrogen on nuclear carbon of linear polymericmaterials having a chain of two to thirty groups, B being a monovalentaromatic radical, and, terminally, two monovalent radicals whichtogether form a polyhalogenated methane.

THOMAS A. FORD.

